The present application relates generally to compositions for sealing a subterranean zone penetrated by a wellbore.
Zeolites are known to be pozzolanic materials and may be activated with alkali or Portland cement in the presence of sufficient water. In most cases, it is possible to accelerate or retard the setting time by using conventional cement additives. However, further properties of a zeolite-containing composition such as compressive strength development, early strength, rheology, and density, for example, are of industrial concern.
Conventionally, a wellbore is drilled using a drilling fluid that is continuously circulated down a drill pipe, through a drill bit, and upwardly through the wellbore to the surface. The next operation usually involves running a pipe string, e.g., casing, into the wellbore, and then cleaning out the wellbore, after which primary cementing operations are typically performed. The pipe is cemented in the wellbore by placing a cement slurry in the annulus between the pipe and the walls of the wellbore. The cement slurry sets into a hard impermeable mass, and is intended to bond the pipe to the walls of the wellbore whereby the annulus is sealed and fluid communication between subterranean zones or to the surface by way of the annulus is prevented.
During any of the above or other operations performed in the wellbore, a number of problems can occur, including difficulty in removing portions of drilling fluid, deposits of filter cake, or inability to achieve a satisfactory bond between the pipe and the walls of the wellbore.
The present embodiments provide zeolite-containing cementitious compositions having enhanced performance in terms of rheological properties and compressive strength. In particular, such compositions are useful in the construction industry and in well cementing.